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CTET 1 Mar 2026 Paper 1, Question 40

Topic: Geometry

Q40

Which of the following statements is not true ?

  1. (1) Sum of two acute angles can be equal to a straight angle.Correct answer
  2. (2) Sum of two acute angles can be equal to a right angle.
  3. (3) Sum of two acute angles can be equal to an obtuse angle.
  4. (4) Sum of an acute angle and an obtuse angle can be equal to a straight angle.

Solution.

CBSE answer: (1)

Answer: (1) Sum of two acute angles can be equal to a straight angle.

  1. Each acute angle is less than 90∘90^\circ, so two of them add to less than 180∘180^\circ; they can never make a straight angle.
  2. 45∘+45∘=90∘45^\circ + 45^\circ = 90^\circ (right angle) and 60∘+50∘=110∘60^\circ + 50^\circ = 110^\circ (obtuse) are possible.
  3. 70∘+110∘=180∘70^\circ + 110^\circ = 180^\circ shows an acute plus an obtuse angle can be straight.